1. Field of the Invention
The present invention relates to a sample operation apparatus in which a sample (specified site) on a substrate is operated by scanning a sample surface to thereby obtain a surface shape or a physical property information of the substrate or the sample.
2. Description of the Related Art
As an apparatus for performing an observation of the surface shape of the sample, and a measurement of the physical property information or the like by measuring the sample, such as electronic material and organic material, in a micro region, there is known a scanning probe microscope such as atomic force microscope (AFM) or scanning tunnel microscope. Further, from the fact that this scanning probe microscope is accurate also as a three-dimensional positioning mechanism, various proposals are made also as a working apparatus of a micro portion.
As an application to an operation (manipulation) of the sample, in which the scanning probe microscope is used, there is contrived one called an AFM tweezers in which the sample is inserted between two probes and the sample is gripped/released.
As this AFM tweezers, in a cantilever used in the scanning probe microscope or the like, there is contrived 1) one in which two carbon nanotubes are attached as a tip onto silicon tip, 2) one in which a carbon nanotube is attached to a glass tube as the cantilever, additionally 3) one in which the two cantilevers are made from a silicon substrate by using MEMS (Micro Electro Mechanical Systems), or the like.
In the tweezers of 1) or 2), an opening/closing of the two carbon nanotubes is performed by applying a static electricity between two carbon nanotube tips and, in the tweezers of 3), there is known one in which an electrostatic actuator like comb teeth is constituted in order to grip by the two cantilevers, or one in which an electric current is flowed to a root of the cantilever and a linear expansion of silicon by a heat generation is used in a drive by being enlarged. (For example, refer to Tetsuya Takekawa, Hajime Hashiguchi, Ei'ich Tamiya, et al. “Development in AFM tweezers for performing manipulation of nanomatter” Denki Gakkai Ronbunshi, E. Trans. SM, Vol. 125, No. 11, 2005.)
Generally, the tweezers operates in a gravitational field, the sample is fixed onto a substrate by its own weight or other adhesion force and, in a case where a gripping force and a pulling-up force of the tweezers exceeds the own weight and the adhesion force, it is possible to grip the sample. Further, also as to a separation from the tweezers, if a grip of the tweezers is released, the sample separates by its own weight from the tweezers and drops to a substrate face.
However, if there becomes such a micro sample that a size of the sample is smaller than about 30 μm in diameter for instance, an effect by the own weight of the sample approximately balances with other adhesion force that the sample undergoes, and a motion such as the grip and the separation of the sample becomes complicated.
Since the AFM tweezers has a purpose of operating the grip and the separation of the sample whose diameter is fairly smaller than 30 μm, it follows that it undergoes large an influence of a force other than the gravity.
Especially, the influence of a static electricity force is large and, in the conventional AFM tweezers, since the sample is electrified by the static electricity force acting between the sample and a probe such as carbon nanotube tips, the sample moves on a substrate, so that there is an issue that the grip is not made well. For example, in a case of the sample, such as glass bead (whose diameter is several μm), on a glass substrate, the glass bead is normally electrified and, if the probe is approached in order to grip the glass bead by the AFM tweezers, the glass bead is adsorbed to the probe or repelled from the probe by the static electricity force between the probe and the glass bead and thus its position changes large, so that the operation such as the grip by the AFM tweezers or the separation is very difficult.